If we leave our battery tender on our 2005 Jeep Grand Cherokee over the weekend when no one drives the car the car will start. If we go away for 2 or more days the car won't start. We can jump start or slow charge the battery and it will work for a few months. We have gone through 4 or 5 batteries and that helps for a while. Someone mentioned a neutral switch drain could be the cause. Has anyone else had this problem?

 

You need to see if you have a short somewhere. Get a volt-ohmmeter with an ammeter function. Disconnect the battery, then reconnect a jumper between the terminals you disconnected. Wait a few minutes for the surge to settle down. Connect the ammeter across those terminals, then remove the jumper. You should read something in the neighborhood of 50 milliamperes or less. (0.050 amperes) If it's more than that, you'll need to start removing fuses until you isolate the current load. Be aware that there is an IOD fuse (ignition off draw) that allows current to flow to the clock and the keyless remote receiver that are always drawing some current as well as the door locks and power seat that can be activated even without the key in the ignition. So if you pull a fuse and the current goes to zero, you have probably found the IOD fuse.
Once you find the truly offending fuse, you'll need to figure out what in its circuit is causing the short and fix it.
This isn't rocket science but some common sense and patience may allow you to avoid an expensive trip to an automotive electrician.
If the car has had some collision damage, there might be a pinched wire somewhere. That would be a good place to start looking.
BY the way, "Forum Issues" is not the best place to pose questions relating to your vehicle. It's for issues related to the forum.